Medium-term Bedrest Whey Protein (MEP) (MEP)

The human being has shown that he can live and work in the space environment, but due to the lack of essential mechanical load on muscle and bone, the fluid-shift as well as alterations in the acid-base balance (mainly on account of nutritional factors), the exposure to microgravity results in a gradual degradation of muscle, bone and cartilage, deconditioning of the cardiovascular system and metabolic changes. Countermeasures to prevent all the deconditioning of the physiological systems are not yet fully effective and require further investigation.

A commonly utilized model of simulating the physiological effects of microgravity on the human organism on ground is the 6° head-down-tilt bed rest. In the present study the model has been used to study potential countermeasures to spaceflight-associated deconditioning.

One of the most constrictive changes appearing during space flight as well as during bed rest, are disuse-induced muscle losses. These are associated with a decrease in muscle protein synthesis, rather then an increase in muscle protein breakdown. Besides an effective training countermeasure, nutritional countermeasures gain respect in this context: supplementing conventional diets with whey protein or essential amino acids has been shown to increase muscle protein synthesis. Due to these anabolic properties whey protein seems promising to counteract disuse-induced muscle wasting.

Drawbacks of a high protein intake are calciuric effects, ascribed to the proton-release when metabolizing sulfur-containing amino acids. The so called 'low grade metabolic acidosis' has also shown to activate osteoclastic bone resorption and muscle protein degradation. Therefore, to maximize the anabolic potential of a whey protein supplementation, the acidogenic properties need to be compensated. As previous works suggest, a shift of acid base balance into the acid direction and the resulting changes in bone and protein turnover may be hindered by supplementing alkaline mineral salts.

In this regard, a mid-term bed rest study was performed in order to investigate the effect of a combined whey protein (0.6 g/kg body weight/day) and potassium bicarbonate (90 mmol/day) supplementation as a potential countermeasure to multiple physiological and metabolic alterations on the human body resulting from real and simulated microgravity.

Study Overview

• Status: Completed
• Conditions: Countermeasure Evaluation
• Intervention / Treatment: Dietary supplement: Whey Protein + Potassium bicarbonate; Other: Control

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Cologne, Germany, 51147
    • DLR German Aerospace Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 45 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Healthy males, 20 -45 years
• BMI: 20 - 25 kg/m2
• Height: 158 - 190 cm
• Weight: 65 - 85 kg
• maximum relative oxygen uptake: 30 - 60 ml/min/kg
• non-smokers
• successful medical and psychological screening
• Willingness to participate in the entire study
• signed informed consent
• social insurance
• Clear criminal background check

Exclusion Criteria:

• Abuse of drugs, medicine or alcohol
• Vegetarians, Vegans
• Migraines
• History of mental illness
• Claustrophobia
• History of: thyroid dysfunction, renal stones, diabetes, allergies, hypertension, hypocalcaemia, uric acidaemia, lipidaemia, hyperhomocysteinaemia
• Rheumatism
• Muscle-, Cartilage- or Joint Injuries
• Gastro-esophageal reflux disease, renal function disorder, Hiatus hernia
• Chronic back pain
• Bone diseases
• Herniated discs
• Achilles tendon injuries
• Cruciate ligament rupture or any other severe knee injury
• BMD more than 1.5 SD < t-score
• History of orthostatic intolerance or vestibular disorders
• Anaemia
• Vitamin D Deficiency
• Positive response in thrombosis screening
• Use of metallic implants, osteosynthesis material
• Porphyria, Blood dyscrasia
• HIV, Hepatitis
• Increased Inner Eye pressure
• Intolerance to local anesthetics
• Participation in another study up to three month before study onset

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MEP-1	Dietary supplement: Whey Protein + Potassium bicarbonate; 0.6 mmol WP/kg body weight + 90 mmol KHCO3 during bed rest; Other: Control; Bed rest without dietary supplement
Experimental: MEP-2	Dietary supplement: Whey Protein + Potassium bicarbonate; 0.6 mmol WP/kg body weight + 90 mmol KHCO3 during bed rest; Other: Control; Bed rest without dietary supplement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in body composition	Baseline, after 21 days of bed rest

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma Volume		Baseline, after 21 days of bed rest
Maximum volume of oxygen uptake		Baseline, after 21 days of bed rest
Isometric torque	During a an Isometric Maximum Voluntary Contraction Test on the knee extensors & flexors, the plantarflexors and dorsiflexors, the elbow extensors & flexors the Isometric Torque will be measured in Nm.	Baseline, after 21 days of bed rest
Muscle fatigue		Baseline, after 21 days of bed rest
Bone metabolism		Baseline, after 2,5,14,21 days of bed rest, 1, 5, 14, 28 days after finishing bed rest
Bone mineral density + content		Baseline, after 21 days of bed rest
Standing balance		Baseline, after 21 days of bed rest
Locomotion	Locomotion will be assessed by Dynamic Gait Index, specific parameters are: total Score and Subscore	Baseline, after 21 days of bed rest
Body mass		Daily for a duration of 35 days
Intracranial pressure		Baseline, after 1,4, 7,10,13,14,15,16,17,18,19,20,21 days of bed rest,1,2,4 days after finishing bed rest
Monitoring of Vitamin K status		Baseline, after 2,5,14,21 days of bed rest, 1, 5 days after finishing bed rest
Fat metabolism		Baseline, after 21 days of bed rest
Glucose metabolism		Baseline, after 21 days of bed rest, 4 days after finishing bed rest
Nitrogen balance		Daily for a duration of 33 days
Energy metabolism		Baseline, after 21 days of bed rest
Glucocorticoid activity		Baseline, after 2,3,7,8,12,13,16,17 days of bed rest, 2,3 days after finishing bed rest
Muscle metabolism		Baseline, after 21 days of bed rest
Acid base balance		Baseline, after 2, 14, 21 days of bed rest, 5 days after finishing bed rest
Sympathetic activity during orthostatic stress	Muscle sympathetic nerve activity is measured by MSNA recording by microneurography technique.	Baseline, after 21 days of bed rest
Visual Orientation	Visual Orientation is assessed by 'Oriented Character Recognition Test' and Luminous Line Test. The main parameter is Score.	Baseline, after 6,12,20 days of bed rest, 2,4 days after finishing bed rest
Plasma galanin and adrenomedullin responses during head up tilt test (orthostatic stress)		Baseline, after 21 days of bed rest
Cartilage metabolism and -thickness		Baseline, after 2,3,5,7,14,21 days of bed rest, 5 days after finishing bed rest
Hematopoetic system	Blood cell count, reticulocytes, Haptoglobin, Bilirubin, Ferritin, EPO, Thrombopoietin, Urinary Urobilinogen and Fecal Urobilinogen (markers of blood cell degradation)	Baseline, after 10, 21 days of bed rest, 1, 28 days after finishing bed rest
Fat accumulation in bone marrow		Baseline, after 10, 21 days of bed rest, 3, 28 days after finishing bed rest
Achilles tendon structure		Baseline, after 21 days of bed rest, 2, 28 days after finishing bed rest
Headache - frequency and quality		Baseline, daily during 21 days of bed rest
Muscle volume		Baseline, after 20, 21 days of bed rest, 3 days after finishing bed rest
Free water and fat content in muscle		Baseline, after 20, 21 days of bed rest, 3 days after finishing bed rest
Orthostatic tolerance	Orthostatic tolerance will be assessed by Head up tilt test. The following parameters are assessed to measure orthostatic tolerance: beat-to-beat heart rate [bpm], beat-to-beat blood pressure [bpm] time to presyncope [min, s]	Baseline, after 21 days of bed rest

Collaborators and Investigators

• Sponsor: DLR German Aerospace Center
• Collaborators: Medical University of Graz; Radboud University Medical Center; Charite University, Berlin, Germany; Manchester Metropolitan University; University of Toronto; University Hospital, Clermont-Ferrand; University of Cologne; University of Ottawa; University Hospital, Lille; European Space Agency; Leiden University Medical Center; University of Milan; Institut Pluridisciplinaire Hubert Curien, Strasbourg, France; Université de Nice Sophia Antipolis

Publications and helpful links

General Publications

• Rudwill F, O'Gorman D, Lefai E, Chery I, Zahariev A, Normand S, Pagano AF, Chopard A, Damiot A, Laurens C, Hodson L, Canet-Soulas E, Heer M, Meuthen PF, Buehlmeier J, Baecker N, Meiller L, Gauquelin-Koch G, Blanc S, Simon C, Bergouignan A. Metabolic Inflexibility Is an Early Marker of Bed-Rest-Induced Glucose Intolerance Even When Fat Mass Is Stable. J Clin Endocrinol Metab. 2018 May 1;103(5):1910-1920. doi: 10.1210/jc.2017-02267.

Study record dates

Study Major Dates

• Study Start: August 1, 2011
• Primary Completion (Actual): April 1, 2012
• Study Completion: December 7, 2022

Study Registration Dates

• First Submitted: July 23, 2012
• First Submitted That Met QC Criteria: July 31, 2012
• First Posted (Estimate): August 2, 2012

Study Record Updates

• Last Update Posted (Estimate): August 2, 2012
• Last Update Submitted That Met QC Criteria: July 31, 2012
• Last Verified: July 1, 2012

More Information

Terms related to this study

• Other Study ID Numbers: ESA-AO-06-BR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No